Nuclear power plants typically contain three major components as shown in FIG. 1: a reactor which produces superheated water which is transported to one or more steam generators; the one or more steam generators which generate steam; and a power turbine, driven by the generated steam, which produces electrical power. Nuclear power plants may have miles of pipes and ducts which must be inspected and examined for corrosion, leakage and damage. These regions include the reactor bowl, the tube sheet, support plates and the tubing within the steam generator.
It is particularly difficult to inspect all areas of the plant including the primary bowl and steam generator. These areas are often highly radioactive and may leak contaminated liquids. Typically, direct human inspection of the key areas of the steam generator and reactor bowl is limited to several minutes per six-month period.
There are a number of issued patents which disclose devices for nuclear power plant inspection and repair. U.S. Pat. No. 4,673,027 discloses a device for inspecting and repairing the tubes of a nuclear reactor steam generator. The device includes a manipulator which is insertible in the chamber and which may be locked onto the tube sheet for supporting remotely controlled and monitored inspection instruments and tools. The manipulator includes a support leg which is adjustable in length in an axial direction, a main arm connected to and movable relative to the support leg and an equipment carrier which is connected to the main arm.
U.S. Pat. No. 4,653,971 discloses a device for selectively positioning a tool carried by a vehicle which moves on a perforated plate, while the device utilizes an elbow which swings a telescoping arm into position. Similarly, U.S. Pat. No. 4,945,979 disclosed an improved robotic arm for effecting a tube plugging operation. The system also includes an elbow control mechanism.
U.S. Pat. No. 4,205,939 discloses an apparatus for remotely repairing the tubes in a steam generator. The device includes a boom pivotally mounted on a column and a system for rotating the column and the boom therewith. The disclosed device further includes a tool which is operable on the tubes.
U.S. Pat. No. 4,231,419 discloses a manipulator for inspecting and repairing the tubes of heat exchangers. An inspection arm is inserted and removed through a lead-in nozzle and a swivel arm carries an extendable and retractable mouthpiece carrier with a mouthpiece which can be aligned into the tube openings. U.S. Pat. No. 4,919,194 discloses a method of positioning a robot for inspecting and maintaining the steam generator within a nuclear plant.
U.S. Pat. No. 4,302,772 discloses a device for television inspection of an inner surface of a closed cylindrical vessel having vertical access and an access hole in the vessel's upper part. The device includes a television camera and at least one flood light for lighting an area to be inspected. The camera is suspended from a flexible tube which is held rigid under torsion and through which pass electricity supply cables for the camera and floodlight.
U.S. Pat. No. 4,424,531discloses an inspection device for inspecting internal spaces in nuclear reactor installations. The device includes a camera arranged on an adjustable tube U.S. Pat. No. 4,967,092 discloses an apparatus for optically checking the inner profile of a tube. The apparatus includes a probe which is positioned in, and movable longitudinally within, the tube.
Finally, U.S. Pat. No. 4,702,878 discloses a device for searching and retrieving objects on a tube sheet of a steam generator. The device includes a sled having a probe and a gripper which is connected to a flexible tube having control means.
While each of the above mechanisms have been utilized to inspect and/or repair of nuclear power plants and include the use of robotic manipulators or arms, none have been successfully utilized to facilitate the easy hand inspection of the primary bowl of the reactor by an operator or the inspection of the steam generator and associated tubing. Most of the above devices require the use of complex mechanical systems which must be controlled from a remote position.
There has been a long felt need for a versatile and all purpose nuclear power plant inspection device which can be used to inspect the reactor bowl, steam generator areas, tubing and ducts, and other areas within the nuclear power plant. There has also been a long felt need for an inspection device which is hand held and portable, which can be used to inspect large portions of the nuclear power plant, and which can be utilized for a variety of non-nuclear power plant applications.